The method of producing saccharides having glucose as the major component by using the cellulosic biomass (hereinafter, refereed as “the biomass”, occasionally) as the raw material includes the enzymatic saccharification production technology, in which saccharides having glucose as the major component are produced by hydrolyzing at least any one of the cellulose and the hemicellulose (hereinafter, referred by “the cellulose and hemicellulose” or “the cellulose or the like”, occasionally) by an enzyme.
Intrinsically, the enzyme (for example, a cellulase) added to the slurry including the biomass preferentially adsorbs to the lignin included in the biomass, rather than adsorbing to the cellulose or the like which is the material intended to be degraded, during enzymatically saccharifying the biomass in the enzymatic saccharification production technology. The enzyme that adsorbed to the lignin is not useful for degrading the cellulose or the like. Therefore, such adsorption is called as the non-productive adsorption. When the enzymes non-productively adsorb to the lignin, the amount of the enzyme functioning in degrading the cellulose or the like, which is the original intention, is reduced.
It is hard to recover the enzymes that adsorbed to the lignin. In addition, it is believed that the mechanism of adsorption of the enzyme to the lignin is based on the hydrophobic adsorption. If the adsorption of the enzyme to the lignin were based on the hydrophobic adsorption, the enzyme would adsorb to the lignin being deformed. Thus, it is believed that the enzyme have lost the originally retained activity. Since the enzyme is extremely expensive, there is a demand for the technology of suppressing the non-productive adsorption of the enzyme to the lignin.
Conventionally, it is known that the addition amount of the enzyme can be reduced by adding BSA (bovine serum albumin) or a surfactant in enzymatically saccharifying the biomass (for example, see Non Patent Literature 1 (NPL 1)).